Answers to: Ubuntu Booting very slowly

Answer by guerda

guerda — Mon, 17 May 2010 11:43:16 -0400

As I looked at your bootchart, I assume you should search for hardware problems.

kblockd and async are both processes for controlling I/O of block devices. Propably one of your block devices is corrupt and lets your linux stop booting.

The boot log shows similar hints:

[  106.005524] sr 0:0:1:0: [sr0] Sense Key : Illegal Request [current]
[  106.005530] sr 0:0:1:0: [sr0] Add. Sense: Illegal mode for this track
[  106.005537] sr 0:0:1:0: [sr0] CDB: Read(10): 28 00 00 00 00 00 00 00 02 00
[  106.005546] end_request: I/O error, dev sr0, sector 0

(Line 501 ff)

Line 445 shows, what sr0 is: A SCSI attached CD drive:

[   93.998132] sr0: scsi3-mmc drive: 16x/48x cd/rw xa/form2 cdda tray

Try the following:

Detach your CD drive.
Boot again.

Good luck!

Answer by memnoch_proxy

memnoch_proxy — Tue, 11 May 2010 20:36:28 -0400

Consider checking your network settings. Your boot might be trying to do something so silly as to be hanging on acquiring a DHCP address or resolving a hostname.

I also suggest checking dmesg and/or /var/log/syslog to check for disk or memory problems. If you're using a spindle disk (not ssd) then you might be encountering a failing sector. Read up on the e2fsck -c option.

Answer by Gareth

Gareth — Tue, 11 May 2010 09:14:02 -0400

Looking at your boot log I noticed these two entries:

[    2.078263] usb 3-2: configuration #1 chosen from 1 choice
[   21.816069] ata1.01: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen

So basically your boot sequence is going from 2 seconds to 22 seconds trying to load a drive. There are a few mentioned possible fixes you can try and the easiest one of these is ... put a disk in your CD/DVD drive and it might help.

There are other very hacky and hard to do fixes which will eventually be resolved. The potential problems relate to Samsung hard disks that have BIOS settings that cause the freeze and a few more.

Answer by abgalphabet

abgalphabet — Tue, 11 May 2010 07:21:30 -0400

In addition to switch off the unnecessary auto-start service via System>Accessories>Startup. You can make use of the duo core of your system by enabling parallel booting by following configuration:

edit /etc/init.d/rc
modify "CONCURRENCY=none" to "CONCURRENCY=startpar" (of course without quote)

Answer by Jimmyfd

Jimmyfd — Tue, 11 May 2010 06:35:43 -0400

In order to reduce start-up-time you can go to System>Accessories>Startup programs and unmark the daemons you do not need to load at default.

In order to reduce startup time I'd advice you to remove just one program at a time, then boot the computer. You'll have to know which programs you don't need at startup else you risk destroying your entire system.

Things such as Bluetooth, Gnome remote desktop and personal file sharing are things that is just there, things that you normally do not use.

Answer by guerda

guerda — Tue, 11 May 2010 05:48:14 -0400

To inspect your boot process, use bootchart. It records your boot process and creates a neat graphic, e.g. sth. like this:

Larger

It works as a daemon and creates a bootchart every time you start your computer. You can optimize your boot process if you parallelize the processes.

Edit:
I inserted Tapan's bootchart. It's very freaky, imho.